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Introduction to Estimating

Seven steps to an accurate project bid, for new estimators

For a contract glazing firm, a bid estimate can make or break a project. An estimate that is too high can cost a bidder the job, while one that is too low or omits elements of a job can cut into margins and affect overall company profitability. 

“If a project is underbid, all subcontractors, not just the glaziers, are placing themselves in quite the predicament,” says Chuck Knickerbocker, curtain wall manager, Technical Glass Products. “If something is missed in the estimate and it is contractually obligated to be delivered, the glazier is essentially giving it away for free. This not only has the potential to negatively impact their bottom line for the project in question, but also for the company as a whole.”

Getting the estimate right, however, is a challenge. Bidding companies must consider every potential material and equipment cost, every person-hour it will take to fully complete the job and related costs, such as potential taxes. “Not only does an accurate estimate set the baseline for project costs, such as material and labor, it also sets the scope of work the glazier is committed to perform,” says Knickerbocker. “Essentially, it’s the first chance on any job to get it right. If the estimate’s wrong, they will pay the price of it being wrong the whole job through.”

“Estimating is both science and art,” adds Ted Derby, project manager, Intertek Building Sciences Group, Intertek. “A real understanding of any project is needed quickly and as complete as possible. Through this real understanding comes accuracy and profitability.” 

This article, the first in Glass Magazine’s Glaziers’ Toolbox series, provides glazing subcontractors with introductory tips for accurate project estimates to help companies avoid financial curveballs once a bid is won. 

1 - Verify the quality of the project plan

If the blueprints or plans are lacking necessary details, don’t guesstimate. Seek out confirmation from the architect through bid requests for information, or make sure unresolved questions are qualified in bid documents. 

When dimensions are not provided, do not scale the drawings in an attempt to determine the dimensions not furnished. While this may result in an adequate dimension, the risk is completely on the person doing the scaling, namely the estimator. Inaccuracies can lead to over- or under-estimating areas and sizes of windows, thereby affecting scope and estimated costs.

2 - Ensure takeoffs are detailed and precise

Make sure material takeoffs are accurate. If the dimensions of a window are wrong, or the number of windows actually required is more than the estimate, a bid will end up being low, the job costs will exceed the estimated costs, and the company will lose money. On the other hand, if the estimate includes more windows than are required, the bid may be higher than a more accurate bid prepared by a competitor, meaning the competitor will win the job by having the lower bid.

3 - Track price changes 

Prices change. An estimator must keep on top of market conditions to correctly determine material costs, and the pay climate in order to identify accurate rates for laborers and craftsmen, making sure to factor in all federal and state payroll costs as well.

4 - Use a checklist

It’s easy to forget things when there is so much to consider and to take into account. Using a checklist helps an estimator keep track of all the details and allows them to add items as they are thought of or come up during the estimating process. There are many estimating template checklists already available on the internet, or an estimator can make one themselves. In either case, edit the checklist each time it is used to be more comprehensive and useful to your task. Mark items that aren’t relevant as NA (not applicable) or remove them completely. Add notes for items that need to be modified to better fit your project. Sometimes items can be combined, or some may need to be broken down further. Note everything on the checklist to make the job of estimating easier.

5 - Determine needs before costs

An estimator must understand the systems being used for each of the window or curtain wall types included in a set of plans, and what materials must be included in the material takeoffs. Additionally, he or she must also determine miscellaneous needs—for example, packaging and shipping materials if a project is out of town and the job is fabricated in a facility. Outside of material costs, estimators must also factor in the costs of equipment and the costs of labor: is special equipment needed? How many person-hours are needed for each task?

6- Provide details for all areas of the estimate

It is expected that every estimator will have more experience and expertise in one area over another. These areas are easy to detail to the extreme. However, it is the areas in which expertise is lacking that need as much detail included as possible. Try to identify project risks, especially in those areas that are less familiar, and factor in their costs. This will allow an estimator to mitigate any potential pitfalls. 

7 - Ask questions

Because of how important accurate estimates are, an estimator should not be afraid to ask questions of either a more experienced estimator or someone with practical, hands-on experience in the specific area(s) in which the estimator has less experience. One of the more important characteristics an estimator can develop is the ability to recognize what they do not know. 

Estimating Essentials from

This article is based on the new Introduction to Estimating course from the National Glass Association’s online learning platform, The course, developed in conjunction with top industry professionals, is part of a larger estimating essentials educational bundle that also addresses reading blueprints.  

There are many intricacies and details that go into an estimate, with the foundation being the project blueprints. Reading and understanding blueprints and plans is essential to determining accurate estimates, neither of which are simple tasks. The new course bundle for addresses these responsibilities. The bundle includes:

— Two eLearning courses covering the essentials: 

— Reading Plans and Blueprints

— Introduction to Estimating

— Glass and Glazing Estimating Essentials Manual offered digitally within each eLearning course

— For a nominal fee, the bundle can also include an exclusive, professionally printed and bound manual.

— Additional resources such as sample commercial plans and more. 

To purchase this bundle and find more course specifics, go to Discounts are available to NGA members. 


Melissa Fischer

Melissa Fischer

Melissa Fischer is instructional designer/ administrator for the National Glass Association. She can be reached at